7.5 Selection and Speciation Flashcards
temporal isolation
organisms breed at different times of year
ecological isolation
different habitats within the same area
behavioural isolation
different behaviour patterns e.g.. courtship behaviours
mechanical isolation
anatomical differences making it impossible for gametes to come together
gametic isolation
incompatibility between gametes and prevent hybrid forming
e.g.. not splitting properly at meiosis
hybrid isolation
organisms interbreed but offspring are infertile
e.g.. horse and donkey can produce a mule but it is infertile
allopatric speciation
new species form from different populations in different areas due to geographical isolation
sympatric speciation
speciation occurring within a population in the same area
anatomical adaptations
changes in the structural features of the organisms body
behavioural adaptations
the way in which an organism acts to increase its chances of survival
physiological adaptations
processes taking place inside the body that increase the chances of survival
genetic diversity
indicates how much genetic variation that exists within a population
evolution
the change in allele frequencies in a population due to natural selection or genetic drift
gene pool
the total sum of all of the alleles of all the genes in a population
stabilizing selection
organisms with alleles that favor the characteristics towards the middle of the range survive .
this occurs when the environment is not changing and it reduces the ranges of possible characteristics
